Press



Jan. 18, 1966 M.VAN DRANEN PRESS 2 Sheets-Sheet 1 Filed July 19, 1963FIG. I

INVENTOR.

BY Mam mus VAN Dam/Eu ATT KN YS Jan. 18, 1966 M.VAN DRANEN PRESS 2Sheets-Sheet 2 Filed July 19, 1963 FIG.2

FIG.3

INVENTOR. MAR1-u5 l AN DRANEN ATTORNEYS 3,229,619 PRESS Marinus vanDranen, Leeuwarden, Netherlands, assignor to N.V. Machinefabriek A.Biilenga, Leeuwarden, Netherlands, a limited-liability corporation ofthe Netherlands Filed July 19, 1963, Ser. No. 296,193 Claims priority,application Netherlands, Aug. 24, 1962, 282,492 2 Claims. (Cl. 100-52)The invention relates to a press comprising a supporting member for thesupport of the article to be pressed and a straight guiding devicefixedly connected to the supporting member which with the aid of anactuating mechanism connected hereto and active under influence of apressure medium is movable along the guiding device to and away fromsupporting member.

With such a press, often equipped with a hydraulic actuating mechanism,the cylinder of the mechanism is usually fixedly attached to a pressuremember or yoke connected to the guiding device, While the piston of themechanism is attached to the movable pressure member or die, which isguided between a heavy frame construction comprising the first mentionedpressure member or yoke, the supporting piece or anvil and a pair ofparallel columns.

The length of the stroke of the movable pressure memher is, of course,determined by the length of the cylinder. When a great stroke length isrequired, e.g. with a cheese press where the article to be pressedconsists of a number of separate units laced on each other, more thenumber of the units should be variable, consequently a considerablelength of the cylinder is required which makes the press more valuablebut is also a disadvantage due to the space required by the press evenwith a horizontal arrangement of the guiding :device. In other words,the height or length of the press could be twice the length of thepiston stroke due to the height of the article to be pressed in itsunpressed condition.

The invention aims at providing :a press which operates over a greatlength and yet is actuated by a press cylinder with a short stroke sothat the press is inexpensive and has few disadvantages due to its smalldimensions. Therefore, a press of the type described in the preamble andmade in accordance with the present invention contemplates using asecond pressure member at the side of the first pressure member facingaway from the supporting piece and which is movable along the guidingdevice. In addition, an actuating mechanism is provided for the movementof the second pressure member and is connected to said second pressuremember with both pressure members alternately attachable and releasablerespectively with regard to the guiding device.

On hydraulically or pneumatically operating the actuating mechanism,which may comprise a cylinder with a movable piston therein with thepress according to the invention, since the pressure pieces arealternately attachable to the guiding device and releasable therefrom,when the second pressure piece which is most remote from the supportingpiece has first been attached to the guiding device and then the firstpressure piece has been released from the guiding device, this firstpressure piece will move to the supporting piece by expansion of theactuating mechanism, on compressing the article about a distance, equalto the expansion movement of said mechanism, after which, afterattaching of the first pressure piece to the guiding device and thenreleasing of the second pressure piece from the guiding device, thesecond pressure piece e.g. by contraction of the actuating mechanism oreg by action of gravity, the operation of an elastic memher orotherwise, will move about the distance of the United States Patent3,229,619 Patented Jan. 18, 1966 contraction in the direction of thesupporting piece, so that the original condition has been obtained, inwhich the pressure pieces, however, have been shifted about a distanceequal to the expansion and contraction movement respectively, along theguiding device, after which the cycle may be repeated.

With an embodiment of the press according to the invention, having anactuating mechanism comprising a cylinder and a piston movable therein,whereas the cylinder space can be brought in communication with a sourcefor a pressure medium, according to the invention the cylinder isattached to the one pressure piece and the piston to the other pressurepiece.

Preferably with a press, the guiding device of which having one or morecolumns, according to the invention the pressure pieces are providedwith an inner deformable sleeve of flexible material embracing thecolumn and an outer non-deformable sleeve of hard material surroundingthe inner sleeve at some radial distance, which sleeves at both ends aresealingly connected to each other and the outer sleeve is attached tothe pressure piece, whereas the annular space between the sleeves can bebrought in communication with the source of the pressure medium, via aduct.

With an embodiment of the press according to the invention one of thepressure pieces is provided with a valve mechanism incorporated in thepressure duct system and the other pressure piece with an actuating rodhaving stops, for cooperating with an actuating member of the valvemechanism, a tension-spring being arranged between both pressure piews,one and another such that in one position of the actuating member of thevalve mechanism, for moving the first pressure piece against the springaction to the supporting piece, pressure medium is sup plied to thecylinder, as well as to the annular space between the sleeves at thesecond pressure piece and then pressure medium is discharged from theannular space between the sleeves to the first pressure piece and at theend of the piston stroke, the actuating member of the valve is broughtinto a second position by cooperation with the actuating rod, in whichposition pressure medium is supplied to the annular space between thesleeves at the first pressure piece and then pressure medium isdischarged from the cylinder as well as from the annular space betweenthe sleeves at the second pressure piece, whereas a reversing valve ispresent in the pressure duct system, by means of which, for moving thefirst pressure piece away from the supporting piece, the communicationof the pressure medium source with the sleeves at one pressure piece andwith the cylinder and the sleeves at the other pressure piecerespectively, is reversible.

The invention will become more apparent from the fol lowing detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a diagrammatical view of the press;

FIG. 2 is a schematic presentation of the circuitry of the hydraulicpressure system; and

FIG. 3 is a cross-section of a pressure chamber illustrating the mannerby which the sleeve grips a column.

The press shown is of the usual vertical arrangement and of thehydraulic type, with a transverse supporting member for the support ofan article to be pressed, a pair of vertical columns 2 attached to thesupport member, which columns at their upper ends are joined by a bridgemember 3 to constitute a fixed frame and a first transverse pressuremember 4, movable up and down between the columns, to which member 4 thepiston rod 5 of an actuating mechanism is attached.

A cylinder 6 of the actuating mechanism has a rather small axialdimension and is attached to a second transverse pressure member 7,which is also guided up and down along the columns. A piston 8 attachedto the piston rod has consequently a short length of stroke. Thepressure members 4, 7 have each been provided at their ends with asleeve-like gripping means embracing the column 2, said means comprisingan inner, easily deformable sleeve 9 (e.g., of rubber) resting againstthe column, and coaxially there around a rigid sleeve (e.g., from metal)which is attached at both ends sealingly to the [rubber sleeve, leavingfree a pressure chamber. Furthermore, the metal sleeve is attached in abore of the pressure member. If a pressure medium (e.g., a liquid underpressure) is admitted into the pressure chamber C between the sleeves 9,10, the rubber sleeve 9 is tightly pressed against the column 2 so thatthe first pressure member 4 is attached to the column. As soon as thepressure medium is discharged from the pressure chamber C betweensleeves 9, 10 the pressure member 4 is released from the columns andthen can be shifted again.

A reservoir, not shown, for the pressure liquid is via pipes, not shown,in communication with the cylinder space above and below the pistonthereof as well as with the pressure chamber C between the sleeves 9, 10of the gripping means.

By now admitting the pressure medium to the gripping means of the secondpressure member 7 and also to the upper side of the cylinder 6 attachedto the said pressure member while the pressure medium of the grippingmeans of the first pressure member 4 is discharged, the pressure member4 will move downwards against the action of tension springs 14, attachedwith their ends to the pressure members 4 and 7. Due to thecounter-pressure by an article to be pressed, member 4 will exertthereon a pressure which amounts to the pressure of the pressure mediummultiplied by the surface of the piston in the cylinder. This only takesplace if the clamping action on the columns 2 of the inner sleeves 9 ofthe gri ping means of the pressure member 7 is great enough to take upthe axial pressure exerted by the cylinder. If that would not be thecase, the pressure member 7 would then slide upwards along the columns.

The axial force which the gripping means of pressure member 4 or 7 cantake up equals the normal force with which the inner sleeves 9 arepressed against the columns, multiplied with the coefiicient of frictionbetween inner sleeve and column. The normal force with which an innersleeve is pressed :against the column is approximately equal to thesurface of the cylinder multiplied by the pressure of the pressuremedium. The press will operate well if the surface of the cylinder 6 issmaller or at most equal to the total surface over which the innersleeves 9 of the gripping means are pressed against the columns 2multiplied by the coefiicient of friction between inner sleeve andcolumn.

As soon as the pressure member 4 has nearly come to the end of theshift, determined by the piston stroke length, with the aid of anoperating rod 11, attached to the .pressure member 4 and having an upperand a lower stop, 11a and 11b respectively, a valve mechanism Acomprising reversing valves 12 and 13 are in communication with pressure7 and controlled by the stop 11a. This valve mechanism A provides achanging over in the circuit of the pressure medium such that at firstthe pressure medium is admitted to the gripping means of the firstpressure member 4 and then the pressure medium is discharged from thegripping means of the second pressure member 7 as well as from thecylinder. As soon as, owing to this, the first pressure member 4 hasbeen attached to the columns and the second pressure member 7 has beenreleased from the columns, the second pressure member 7 will movedownwards under influence of the gravity action and under the action ofthe tension springs 14. The downward movement of the second pressuremember 7 will continue till the operating rod 11 again changes over theoperation of the valve mechanism A via the stop 11b, by which theoriginal connection of the circuit of the pressure medium is restored.For this purpose first of all the pressure medium is again admitted tothe gripping means of the second pressure member 7 and also to the upperside of the cylinder 6, thereafter the pressure medium is dischargedfrom the gripping means of the first pressure member 4. If the assembly,constituted by the first and second pressure members and the cylinderwith its piston, is located at the upper side of the columns 2, it willmove downwards step-wise until it meets a counter-pressure as long asthere is still a distance present between it and the article to bepressed. The stages are of course equal to the relatively short strokeof the piston 8 in the cylinder. When the compression which the articleis experiencing is greater than the piston stroke, the assembly willsimply move a step further downward at the end of the said stroke.

In order to complete the press action, a second reversing valve B, shownin the circuitry of the pressure medium (FIG. 2), can be actuated byhand so that on actuating a hand lever (not shown) of said secondreversing valve from a first position for the above-described step-wisedownward movement of the assembly to a second position, a changing overin the circuit will be contained such that the sequence of attaching thegripping means to the columns is reversed. Instead of the gripping meansof the second pressure member 7 being clamped on the columns and theupper side of the cylinder 6 being supplied with pressure fluid, thegripping means of the first pressure member can be clamped on the saidcolumns to coincide with the application of pressure on the lower sideof the cylinder 6, and directly thereafter to have the release of thegripping means of the second pressure member 7 from the columns takeplace, will provide a stepwise upward movement of the press assembly.

When the press is only used for pressing articles which experience apermanent change of shape, the gripping means of the first pressuremember will never need to take up an axial pressure. They will only haveto be able to carry the weight of the second pressure member witheverything attached thereto. In that case the surface with which thesleeve 9 of the gripping means of the first pressure member grips thecolumn will be much smaller, or in other words, the sleeves 9 can bemuch shorter than the sleeves 9 of the gripping means of the secondpressure member 7.

I claim:

1. A press comprising two columns held in fixed parallel relationship, atransverse supporting member permanently fixed to said columns forsupporting an article to be pressed, a first transverse pressure memberbeing slidably mounted on said columns, a second transverse pressuremember being slidably mounted on said columns between said firstpressure member and said supporting member, flexible sleeve-likegripping means mounted on each end of the pressure members and slidablyreceiving the press columns therein, tension spring means beingpositioned between the pressure members and having the ends thereofconnected to the pressure members, said spring means biasing saidpressure members toward each other, a pressure cylinder mounted on saidfirst pressure member, a piston reciprocably mounted within saidcylinder, a piston rod having one end connected to said piston and theother end thereof connected to said second pressure member, saidgripping means each comprising a flexible inner sleeve and a rigid outersleeve, the inner and outer sleeves being sealingly connected to eachother and having a space therebetween for forming a pressure chamber, aninlet for introducing a pressure fluid to each of said pressurechambers, said inlet also serving as an outlet for exhausting thepressure fluid, reversing valve means for supplying and exhaustingpressure fluid to the inlet of the pressure chambers and to the pressurecylinder, and means carried by said second pressure member to operatethe reversing valve, said gripping means serving to adjustably Positionsaid pressure members along said columns, the

reversing valve means serving to introduce fluid pressure to thegripping means of said first pressure member'and to the cylinder and toexhaust fluid pressure from the gripping means of said second pressuremember whereby the second pressure member is moved by said piston rodto- Wards said supporting member against the action of said spring meansWhile said first pressure member is held in engagement with said columnsuntil said piston rod reaches a predetermined point and then a changeover takes place in the pressure fluid circuit whereby the secondpressure member is clamped to said columns by said gripping members andsaid first pressure member is unclamped from said columns and allowed tobe pulled towards said second pressure member by the action of saidspring means.

2. A press according to claim 1 in which said reversing valve meansincludes a first valve mounted on said first pressure member, anactuating rod mounted on said second pressure member, a duct systemthrough which the fluid pressure flows, and a second, manually operated,valve, the second valve being adapted to control the direction ofmovement of the pressure members as a unit either towards or away fromsaid supporting member, said actuating rod having first and second stopsfor engaging and operating said first valve.

References Cited by the Examiner UNITED STATES PATENTS 697,287 4/ 1902Spaulding 100-269 X 1,586,923 6/1926 Townsend 24--263.5 2,413,866 1/1947Dulaney 100266 X 2,417,697 3/ 1947 Loomis 100-269 3,015,142 1/1962Rosanoff et a1 24-263.5

FOREIGN PATENTS 880,540 1/ 1943 France.

770,293 3/ 1957 Great Britain.

WALTER A. SCHEEL, Primary Examiner.

20 CHARLES A. WILLMUTH, Examiner.

